This is is an ancestor of the slide-rule, and one of the first computers.

They were invented in the mid. 16th century by John Napier, who is a delight to read about all by himself. He was a Scot, and had some peculiar ideas about the pope– but worry not. He wasn’t much loved by his fellow Presbyterians, either, because he was also known as being an alchemist and aficionado of the occult. Weirdly, alchemy, astrology, and the occult were considered more separate things in those days, for… complicated reasons.

However, we can assure ourselves that he was at least a somewhat Christian wizard, presumably, if his obsession with the Book of Revelation means anything. Alas, the world was supposed to end in 1550. I’m sure the Mayans feel his pain.

Or not– they might simply say that the calendar needs a reboot, and that it doesn’t mean that the world ends. But I haven’t talked to any lately, so I don’t know. (They do still exist in places… but usually in obscure mountain villages in South America)

Anyway, this is math, not superstition. But odd how closely the two ran in certain circles.